#include <iostream>
using namespace std;

// 求圆，三角形，矩形的面积

// 圆
double getarea(double r)
{
    return 3.14 * r * r;
}
// 三角形
double getarea(double bottom, double h)
{
    return bottom * h / 2;
}

// 矩形
int getarea(int bottom, int length)
{
    return bottom * length;
}

// 梯形
double getarea(double up_bottom, double down_bottom, double h)
{
    return (up_bottom + down_bottom) * h / 2;
}

int main()
{
    cout << "圆面积:" << getarea(2) << endl;
    cout << "三角形面积:" << getarea(2.0, 3.0) << endl;
    cout << "矩形面积:" << getarea(2, 3) << endl;
    cout << "梯形面积:" << getarea(2, 3, 4) << endl;
}